Sequence Of Operation; Pressure Service Ports; Defrost Cycle - Compu-aire CELHP Installation, Operation, Maintenance And Parts Manual

SEQUENCE OF OPERATION

energized by manual fan sw~tch on subbase for constant a x circulation.
solenoid coil on reversing valve controls heating cycle operation.
one allowing "Auto" changeover fron cycle to cycle and the other constantly energizmg solenold coll during
heating season and thus elininating pressure equalization nolse except during defrost, are to be used. On
"Auto" option. a circuit is conpleted from R-Ul and R-Y on each heating "on" cycle,
valve solenoid and pulling in compressor contactor startlng compressor and outdoor notor.
starting indoor blower motor. Heat Pump heating cycle now in operation. The second option has no "Auto"
changeover position. but instead energizes the revering valve solenoid constantly whenever the systen sw~tch
on subbase is placed in "Heat" position. the
R-Y
demand for heat completes
mtor. R-G also make starting indoor blower motor.

PRESSURE SERVICE PORTS

observed. Pressure curves can be found later in the nanual covering all nodels on both cooling and heatlng
cycles. It is imperative to match the correct pressure curve to the unit by nodel number.

DEFROST CYCLE

The defrost cycle is controlled by temperature and time on the solid state heat p u ~ p control,
is or below. This coil temperature is sensed by the coil sensor nounted near the bottom of the
the heat control and the defrost timer will start.
After 6 0 or
node.
During the defrost node, the refrigerant cycle switches back to the cooling cycle, the outdoor mtor
electric heaters are energized, and hot gas passing through the outdoor coil me1 ts any accunulator frost.
control which will return the system to heating operations automatically.
If
cycle, the heat punp control will restore the system to heating operation automatically after 10 minutes.
circuit, pulling in compressor contactor starting compressor and outdoor
or below. the coil sends a signal to the control logic of
the coil sensor will send a signal to the heat punp
Two
also make
R.
A thermostat
pressures can be
stops,